The Kessler Syndrome
Space debris. Credit: ESA

The Kessler Syndrome

21/01/2021Written by Alex Thompson

A lot of us dream of going to the Moon, or travelling to Mars, but a very real problem a little closer to home could make this impossible.

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Space debris. Credit: ESA

A lot of us dream of going to the Moon, or travelling to Mars, but a very real problem a little closer to home could make this impossible.

What is the reality that we could all become trapped on our own floating rock in space?

Luckily scientists are working on a way to stop this coming to fruition and ensure space travel can continue for many years to come.

Retired astrophysicist and former NASA scientist Donald Kessler Credit: ESA

The Kessler syndrome was first proposed in 1978 by NASA scientist Donald J. Kessler. This was shortly after the Space Race and the number of satellites being sent into low Earth orbit (LEO) was accelerating rapidly.

Kessler proposed a theoretical scenario where the number of objects in LEO would become so vast that it would cause a chain of events that could eventually stop us leaving Earth.

Kessler’s theory is that if we keep launching into space without a plan of bringing things back down, it would cause LEO to reach a critical mass where collisions between objects would inevitably begin to happen.

These impacts would create more debris, which in turn would create more collisions. This chain reaction would continue until the entire orbital space is covered with space junk and becomes impossible to navigate or use.

This sequence of graphics show the growing quantity of tracked space junk and operating spacecraft orbiting Earth over time. Credits: NASA

An overcrowded orbital space could mean our dreams of going to the Moon or further would be dashed.

Not only this, but robotic missions would not be able to leave Earth either, with exploration of our Solar System and its planets stopped in its tracks.

Even space telescopes would become a thing of the past, and our current spacecrafts in LEO would likely have been destroyed in the prior collisions.

The way we live our everyday lives could dramatically be altered as well.

In today’s world we rely on satellites more than ever before, from communications to security, from GPS to the internet.

If our current satellites our destroyed with no way of replacing them, the modern world as we know it cannot exist, causing an unparalleled economic and humanitarian crisis.

Pigs in Space Credit: Disney

When Kessler proposed his theory he stated he believed it could become reality in 30 to 40 years. We have just passed the later part of that prediction and whilst we have not yet seen the Kessler syndrome in full effect some experts believe we are close to critical mass.

Currently over 500,000 pieces of space debris have been counted, with millions more so small they are impossible to track.

These pieces of space junk travel at over 17,000 mph, meaning even a 1 cm fleck of paint could have the same destructive effect as an object the size of a domestic adult pig travelling at 60 mph on Earth.

ClearSpace-1 captures Vespa Credit: ClearSpace SA

It’s not all doom and gloom; some of the world’s top space scientists are devising solutions to stop this becoming reality. The good news is that prototypes have already been tested and missions have been scheduled to help clean up our orbit. The bad news is it involves sending more things into space.

In 2018 a British satellite was launched 300 km above the Earth and successfully demonstrated its plan to capture debris. RemoveDebris, a project lead by the University of Surrey and assisted by other organisations including Airbus, captured a shoebox-sized object by smothering it in a huge net.

The following year the project successfully captured another piece of dummy debris, this time using a harpoon-object to capture the item. The final part of the plan will see a giant membrane deployed to pull the object towards Earth, so it burns up safely in our atmosphere.

ESA recently signed the contract for a mission that will remove the first piece of large debris from of orbit.

Due to launch in 2025, ClearSpace-1 will use the net method to capture the Vega Secondary Payload Adapter (VESPA) before destroying itself and the captured item on re-entry.

ESA hope this will pave the way for future missions to clean up our orbit and allow space ventures to continue for many years to come.

About the author: Alex Thompson is a Space Communications Presenter at the National Space Centre.